Chronograph movement

ABSTRACT

This invention is exemplified by a hammer made in two pieces, a body piece and a lever piece. The hammer is used to return heart cams such as are used in stopwatches and counting devices to the zero position when a button is pressed. The hammer disclosed consists of a pivoted part which coacts with the button and a lever part which is held between the pivoted part and a platen in such a way that it drives the heart cams to zero position when the pivoted lever engages it at one point.

Elite tates Patet achmann [54] CHRONOGRAPH MOVEMENT [72] inventor: PeterBachmann, Bettlach, Switzerland [73] Assignee: Ebauches Bettlach S.A.,Bettlach, Switzerland [22] Filed: June 8, 1970 211 Appl. No.: 44,512

[30] Foreign Application Priority Data June 10, 1969 Switzerland 8820/69[52] ..58/74 [51] .G04f 7/04 [58] Field of Search ..58/76, 74

[56] References Cited UNITED STATES PATENTS 3,495,397 2/1970 Dubois..5s/74 Feb.22,1972

FOREIGN PATENTS OR APPLICATIONS 1,519,224 2/1968 France ..58/74 PrimaryExaminer-Milton Kaufman Attorney-Stevens, Davis, Miller & Mosher [57]ABSTRACT This invention is exemplified by a hammer made in two pieces. abody piece and a lever piece. The hammer is used to return heart camssuch as are used in stopwatches and counting devices to the zeroposition when a button is pressed. The hammer disclosed consists of apivoted part which coacts with the button and a lever part which is heldbetween the pivoted part and a platen in such a way that it drives theheart cams to zero position when the pivoted lever engages it at onepoint.

4 Claims, 2 Drawing Figures PATENTEBFEB22 1912 &

CHRONOGRAPII MOVEMENT The present invention has for its object a watchmovement comprising a zero return hammer for cooperation with heart camsto assure the return to zero of the indicating members, this hammerbeing formed of at least two distinct parts connected to each other insuch fashion as to permit a limited displacement of one of the partsrelative to the other.

Theprincipal purpose of this invention is to provide a solution to aproblem which is presented when one actuates the hammer of a watchmovement to cause it to bring to zero simultaneously several indicatingmembers, for example the second hand and the minute hand of a stopwatchas when one presses on the return to zero button after the stopping ofthe watch.

Generally, the zero return hammer is constituted of a cut and foldedpiece which pivots around a screw carried on the platen of the movementand which presents as many arms as there are heart cams to actuate. Thehammer is generally moved into engaging position when one presses on theengaging push button and it is directly actuated by the return to zerobutton so as to pivot about its axis when one presses the pushbutton.The extremities of the arms of the hammer each come into contact withone of the heart cams and drive it in the starting position. Thedisplacement of the pushbuttons and of the hammer are in generalassisted by springs one of which, it could be, is cut out with thehammer but the parts which actuate the heart cams are rigidly connectedto the principal part of the body of the hammer. As a consequence toassure the return to zero of all the indicating members, it is necessarythat the contours of the elements be exactly adjusted so as to avoidthat one or the other of these elements should present a slight playwhen the others are in the zero return position. In the movements of thecounters and watches known up to the present, it is necessary to file,polish or adjust the hammers of each piece so as to have a correctlyfunctioning return to zero for each of the heart cams that has to beactuated. It is therefore evident that by avoiding the necessity for anadjustment of each hammer one simplifies manufacture and particularlythe operations of assembly and quality control.

There are already known watch movements in which the part which formsthe hammer is formed of two pieces pivoting on one another, a springbeing biased between these two pieces. Each one of the pieces comprisesan arm the extremity of which cooperates with the heart cams. Thisarrangement naturally avoids the adjustment difficulties of the extrememargins of the two arms of the hammer. One of the two pieces constitutesthe body of the hammer and pivots on the support for the movement. It isthis part which is actuated by the return to zero pushbutton. Meanwhileat the time of operation of the return to zero, the heart cam isactuated by the piece connected to the body of the hammer by a springand thus is influenced only by the force resulting from the loading ofthis spring. The return to zero conditions are not identical for the twoheart cams. This solution is revealed as unacceptable in a movement of achronograph and the invention envisages the establishment of a rigidconnection between each heart cam and the push buttonthrough theintermediary of the different parts of the hammer at the moment of thereturn to zero.

In a watch movement according to the invention, this objective isattained by the fact. that one of said parts is pivotally mounted on theplaten for movement and the other part is connected to the first one soas to hold the two heart cams in zero position when pressed at one pointby the first one.

The annexed drawing shows, by way of example, an embodiment of watchmovement according to the invention.

FIG. I is a fragmentary top plan view; and

FIG. 2 is a view in section taken on the line II-II of FIG. 1.

In the drawing the platen or support 1 of the watch movement is acircular disc approximately one-fourth of the surface of which is shown.In its center, this platen has an opening which permits passagetherethrough of a second hand shaft on which there is mounted a sleeve 2fixed to a heart cam 3. The position of this heart cam and of the sleeve2 is conventional and will not be described further in detail. Thesleeve 2 protrudes through a central opening of the watch face (notshown) and carries a second hand at its end which lies above the watchface. The actuating means which puts the second hand shaft in rotationare not shown and are arranged in the usual way.

The movement described includes also a minute totalizer the indicatingmeans for which is mounted on the sleeve which pivots about a shaftadvancing step by step once each minute. The magnitude of each step ofangular displacement which the shaft accomplishes for each rotation ofsleeve 2heart cam 3 unit is equal for example to one-thirtieth of arevolution or 12. The heart cam 5 is attached to the sleeve 4 andextends a little distance between the center and margin of the platen 1.

As the means of control, the described watch movement includes anengaging and disengaging lever (not shown). which presents two littletongues turned down to the plane of the platen and sticking out from theside of the movement so as to cooperate with two pushbuttons, one forthe engagement of the second hand and the other for stopping it. Themovement also includes a return to zero hammer 6 which is composed of ahammer body 7 and of a hammer lever 8. These two pieces are of cut sheetmetal and are interconnected. The hammer body 7 has a little tongue 9which is turned down at 90 and engages in a notch 10 in the periphery ofthe platen. This little tongue coacts with the return to zeropushbutton. A resilient arm 11 left from the cutting out of the body 7plays the role of a return spring. The end of the arm 1 l is pressedagainst a stud l2 fixed in the platen. In addition, the body 7 of hammer6 pivots on the screw bearing reference numeral 13 which is threadedinto the platen. The body of the spring presents a little tongue 14twice bent 90 and engages in the slot 51 of the platen. Thanks to theseelements, the body 7 of hammer 6 can be mounted on the platen 1 so as topivot about the axis of the screw 13. The projection 16, which is alongthe edge of the body 7, is designed to cooperate with the engagement anddisengagement lever. When the hammer is in the position shown in thedrawing, the engagement and disengagement lever rests on the projection16. Thus when one presses the engagement push button, the pivoting ofthis lever displaces the body of the hammer 6 in the counterclockwiserotation as viewed in FIG. 1. In these conditions, the lever 8 of thehammer moves away from the heart cams 3 and 5, and the movement beingengaged, the second hand immediately begins to turn around its axiswhile the minute totalizer advances automatically one step for eachrotation of the second hand.

In addition to the elements mentioned the body 7 of the hammer 6presents an elongated cut out 18 limited at its two extremities by twolittle tongues 19 and 20 located in the plane of the body of the hammerand each presenting a reentrant flange 20a and 19a. In addition, thebody of the hammer 6 is cut out with two little tongues 21 and 22 whichare bent to extend in a plane parallel to that of the body 7 of thehammer 6 but slightly offset from it in the direction opposite to theplaten as one sees in FIG. 2. The little tongues 21 and 22 are notthemselves exactly parallel to the body 7 of hammer 6 but are disposedslightly obliquely in such a way that their ends rest on the lever 8 ofhammer 6. The latter is made of a plain piece of cutout sheet metal ofthe same thickness as the body 7 of the hammer. It is maintained inplace on the platen 1 by the little tongues 21 and 22. Additionally itis retained in a longitu dinal sense by the little tongues 19 and 20.Finally it is connected to the body of the hammer by the reentrantflanges 19a and 20a which surround its two extremities The internallengthwise boundary presents located between the extremities, therounded peak of which is in contact with a part of the edge of thecutout 18. Finally the lever 8 of the hammer has two striking elements24 and 25 which control the heart cams 3 and 5.

When one wants to pivot the hammer away from the position ofdisengagement in the clockwise sense as viewed in FIG. 1, pressing ofthe push button which acts on the little tongue 9 brings the twoelements 24 and 25 in contact with the heart cams 3 and 5. If one ofthese elements enters in contact with a triangular projection 23 theheart cam which it controls before the other, it produces a slightpivotal movement of the lever 17 around point 23 which brings the otherelement very rapidly into contact with its heart cam. At the end of themovement of the hammer the two heart cams are found at zero, the twoelements 24 and 25 are each in contact with one of them, and the body ofthe hammer is found in a position such that the projection 23 restsagainst the back ofthe cutout 18.

While the present invention has been described in connection with astopwatch, it can be utilized in all sorts of movements for actuating acounting type indicating means and a totalizer arranged in such a waythat the two can be returned I to zero simultaneously whether the devicebe a watch or merely some other sort of counter.

What is claimed is:

l. A watch movement, comprising at least two heart cams for controllingthe return to zero of interval indicating means; a support member; and ahammer comprising first and second parts, said first part being mountedfor pivotal movement on said support member, said second part havingsurfaces for en gaging said heart cams, said first part having tonguesfor retaining said second part in substantially the same plane as saidfirst part and for holding said second part against said support member,said second part having a generally triangular projection, the peak ofsaid projection engaging an edge portion of said first part andconstituting a pivotal point for said second part, the edge portion ofsaid second part opposite said projection having two further projectionsengaging each of said heart cams, respectively, wherein upon pivotalmovement of said first part said edge portion thereof engages saidtriangular projection to cause said further projections to engage saidheart cams to move them to their respective zero positions.

2. A movement according to claim 1 in which the body part of the hammerhas means to encage the extremities of the lever part to prevent it frommoving in the longitudinal sense.

3. A movement according to claim 2 in which said encaging means includesreentrant hooks holding the hammer lever with the hammer body while atthe same time permitting limited play between the two pieces.

4. A watch movement comprising a support member; at least two heartcams; and a hammer comprising first and second parts extending insubstantially the same plane, said first part having a cutout portioncomprising a striking edge portion and two reentrant edge portions, saidfirst portion being pivotally mounted on said support member, saidsecond part loosely engaging said cutout portion and having two strikingelements engaging said heart cams, respectively, said second partfurther having a pointed portion which engages said striking edgeportion, said striking elements comprising means to return said heartcams to zero upon pivotal movement of said first part, said second partstill further having two return means spaced apart on both sides of saidpointed portion, said return means cooperating with said reentrant edgeportions to displace said second part away from said heat cams when saidfirst part is moved from an engagement position with said second partinto a position out of engagement therewith.

1. A watch movement, comprising at least two heart cams for controllingthe return to zero of interval indicating means; a support member; and ahammer comprising first and second parts, said first part being mountedfor pivotal movement on said support member, said second part havingsurfaces for engaging said heart cams, said first part having tonguesfor retaining said second part in substantially the same plane as saidfirst part and for holding said second part against said support member,said second part having a generally triangular projection, the peak ofsaid projection engaging an edge portion of said first part andconstituting a pivotal point for said second part, the edge portion ofsaid second part opposite said projection having two further projectionsengaging each of said heart cams, respectively, wherein upon pivotalmovement of said first part said edge portion thereof engages saidtriangular projection to cause said further projections to engage saidheart cams to move them to their respective zero positions.
 2. Amovement according to claim 1 in which the body part of the hammer hasmeans to encage the extremities of the lever part to prevent it frommoving in the longitudinal sense.
 3. A movement according to claim 2 inwhich said encaging means includes reentrant hooks holding the hammerlever with the hammer body while at the same time permitting limitedplay between the two pieces.
 4. A watch movement comprising a supportmember; at Least two heart cams; and a hammer comprising first andsecond parts extending in substantially the same plane, said first parthaving a cutout portion comprising a striking edge portion and tworeentrant edge portions, said first portion being pivotally mounted onsaid support member, said second part loosely engaging said cutoutportion and having two striking elements engaging said heart cams,respectively, said second part further having a pointed portion whichengages said striking edge portion, said striking elements comprisingmeans to return said heart cams to zero upon pivotal movement of saidfirst part, said second part still further having two return meansspaced apart on both sides of said pointed portion, said return meanscooperating with said reentrant edge portions to displace said secondpart away from said heat cams when said first part is moved from anengagement position with said second part into a position out ofengagement therewith.